Shudder during idle?

Good morning all,
I've a 2006 CTS with 37k on it. While sitting in park, or while at red lights, I am noticing a shudder every 15-20 seconds. Some strong enough that makes me look at dash readouts to ensure the car did not die. I have noticed that it does not seem to have as much power as I expected, especially from the line. However, being that I've only had the car for 3 months and my previous vehicle was a V8 Tundra, I just assumed that it was because of the smaller engine. I still think it should have more power, though. :-/

On top of that...I have to have about $1000 in work done today due to a locked up caliper on the passenger side causing a shimmy. Ah, FML!

Re: Shudder during idle?

Originally Posted by DevilDoc68

Good morning all,
I've a 2006 CTS with 37k on it. While sitting in park, or while at red lights, I am noticing a shudder every 15-20 seconds. Some strong enough that makes me look at dash readouts to ensure the car did not die. I have noticed that it does not seem to have as much power as I expected, especially from the line. However, being that I've only had the car for 3 months and my previous vehicle was a V8 Tundra, I just assumed that it was because of the smaller engine. I still think it should have more power, though. :-/

On top of that...I have to have about $1000 in work done today due to a locked up caliper on the passenger side causing a shimmy. Ah, FML!

Thoughts? Suggestions?

Doc

Hi Doc,

I see you have been given some great advice from other forum members. I am sorry you have to repair your vehicle and I understand how other issues arising on top of another vehicle issue can be frustrating. If there are ever questions or concerns you would like to further discuss, please private message me.

I was wondering the same about my 05. Its like it almost stalls when idling but only every 15-30 seconds. No lights on dash or anything. I've only had her for a month now and other then some weird hard shifts every once in a while alls good.

I was wondering the same about my 05. Its like it almost stalls when idling but only every 15-30 seconds. No lights on dash or anything. I've only had her for a month now and other then some weird hard shifts every once in a while alls good.

Check all the vacuum lines, casper the ghost likes to unplug one from time to time, my car had a slight rough idle when I was at a stop or in bumper to bumper traffic and would hard shift down sometimes also, so I popped the hood and seen a vacuum hose not connected to anything so I found out were it went and the car as idled perfect and shifted down perfect every since

Re: Shudder during idle?

Thanks for the shout out. I am here to help in any way possible! I am not able to offer any technical advice, because I am not a certified technician, however, I do my best to utilize my resources and make contact with the appropriate person to further assist a customer.

Re: Shudder during idle?

Forget vacuum it WILL NEVER act so sudden, It is electrical problem, misfiring 100%
I had same issue, end up being bad coil, actually two of them. It is going to be hard to find which one is bad since ECM will not flag misfiring on low
rpms.
I had to wait until started acting more often, usually under heavy load, wet weather condition and low rpms like 1500-2000.

Forget vacuum it WILL NEVER act so sudden, It is electrical problem, misfiring 100%
I had same issue, end up being bad coil, actually two of them. It is going to be hard to find which one is bad since ECM will not flag misfiring on low
rpms.
I had to wait until started acting more often, usually under heavy load, wet weather condition and low rpms like 1500-2000.

Actually it will trigger a misfire on low rpm, just no check engine light. BUT you have to use a scan tool that can read live codes. My brother has such a scan tool at his shop. Brought my CTS by there and we counted the misfires as they were happening, on cylinder 2 in my case.

Re: Shudder during idle?

An actual customer service rep from Cadillac on this site? and they actually respond? That is just amazing.

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I too am starting to get that shudder at idle, when it is hot out with the A/C on.
I have a couple of toys to play with for scanning (torque app and the bluetooth obdii connector) so I can try to check on that.

It is a momentary shudder that sort of feels like a miss fire, heck it probably is.

Re: Shudder during idle?

Originally Posted by Kael

An actual customer service rep from Cadillac on this site? and they actually respond? That is just amazing.

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I too am starting to get that shudder at idle, when it is hot out with the A/C on.
I have a couple of toys to play with for scanning (torque app and the bluetooth obdii connector) so I can try to check on that.

It is a momentary shudder that sort of feels like a miss fire, heck it probably is.

Hello Kael,

Yes, I am here to help you and anyone else out on this site the best I can! I can be reached via private message to further discuss any concerns or questions.

Re: Shudder during idle?

Forget those representatives, you will just wast your time. It is coil or spark plug 100%, I had exact same issue AC on in drive, shudder, low RPM driving under load shudder ETC. Have good scanner with real time scan and catch it while is misfiring.

Re: Shudder during idle?

Saying to forget the actual Cadillac customer service personnel is kind of rude. Even if you know the exact problem, discrediting professionals that take the time to be here isnt necessary.

It does sound like you have a misfire somewhere.

I do not get a shudder, so I guess this really doesnt belong here at all, probably. But I have noticed that my idle at start-up is sometimes different. Most of the time, I would say idle is 650rpms. Sometimes, it starts up all excited. Idles at 1,100. Nothing else is different from the last time. I didnt leave the A/C on, or anything like that. Car just starts up excited sometimes for apparently no reason.